Method of allocating csi-rs for beam management

ABSTRACT

The disclosure relates to a communication technique of fusing a fifth generation (5G) communication system for supporting higher data transmission rate beyond a fourth generation (4G) system with an Internet of things (IoT) technology and a system thereof. The disclosure may be applied to intelligent services (e.g., a smart home, a smart building, a smart city, a smart car or a connected car, health care, digital education, a retail business, security and safety related service, or the like) based on the 5G communication technology and the IoT related technology. The present disclosure relates to a method and apparatus for searching for or determining information on a beam that a UE or a base station can use for signal transmission and reception in a mobile communication system.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 15/934,490, filed on Mar. 23, 2018, which will be issued as U.S.Pat. No. 10,701,580 on Jun. 30, 2020, which is based on and claimedpriority under 35 U.S.C. § 119(a) of a Korean patent application number10-2017-0037155, filed on Mar. 23, 2017, in the Korean IntellectualProperty Office, and of a Korean patent application number10-2017-0057055, filed on May 4, 2017, in the Korean IntellectualProperty Office, and of a Korean patent application number10-2017-0101585, filed on Aug. 10, 2017, in the Korean IntellectualProperty Office, the disclosure of each of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The disclosure relates to a method and an apparatus for searching for ordetermining information on a beam that a user equipment (UE) or a basestation can use for signal transmission and reception in a mobilecommunication system.

BACKGROUND

To meet a demand for radio data traffic that is on an increasing trendsince commercialization of a fourth generation (4G) communicationsystem, efforts to develop an improved fifth generation (5G)communication system or a pre-5G communication system have beenconducted. For this reason, the 5G communication system or the pre-5Gcommunication system is called a beyond 4G network communication systemor a post long term evolution (LTE) system. To achieve a high datatransmission rate, the 5G communication system is considered to beimplemented in a very high frequency (mmWave) band (e.g., like 60 GHzband). To relieve a path loss of a radio wave and increase a transferdistance of the radio wave in the very high frequency band, in the 5Gcommunication system, beamforming, massive multiple input and multipleoutput (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analogbeam-forming, and large-scale antenna technologies have been discussed.Further, to improve a network of the system, in the 5G communicationsystem, technologies, such as an evolved small cell, an advanced smallcell, a cloud radio access network (cloud RAN), an ultra-dense network,a device to device communication (D2D), a wireless backhaul, a movingnetwork, cooperative communication, coordinated multi-points (CoMP), andreception interference cancellation have been developed. In addition tothis, in the 5G system, hybrid frequency shift keying (FSK) andquadrature amplitude modulation (QAM) modulation (FQAM) and slidingwindow superposition coding (SWSC) that are an advanced codingmodulation (ACM) scheme and a filter bank multi carrier (FBMC), anon-orthogonal multiple access (NOMA), and a sparse code multiple access(SCMA) that are an advanced access technology, and so on have beendeveloped.

Meanwhile, the Internet is evolved from a human-centered connectionnetwork through which a human being generates and consumes informationto the internet of things (IoT) network that transmits/receivesinformation between distributed components, such as things and processesthe information. The internet of everything (IoE) technology in whichthe big data processing technology, and the like, is combined with theIoT technology by connection with a cloud server, and the like, has alsoemerged. To implement the IoT, technology elements, such as a sensingtechnology, wired and wireless communication and network infrastructure,a service interface technology, and a security technology, have beenrequired. Recently, technologies, such as a sensor network, machine tomachine (M2M), and machine type communication (MTC) for connectingbetween things has been researched. In the IoT environment, anintelligent Internet technology (IT) service that creates a new value inhuman life by collecting and analyzing data generated in the connectedthings may be provided. The IoT may be applied to fields, such as asmart home, a smart building, a smart city, a smart car or a connectedcar, a smart grid, health care, smart appliances, and an advancedhealthcare service, by fusing and combining the existing informationtechnology (IT) with various industries.

Therefore, various tries to apply the 5G communication system to the IoTnetwork have been conducted. For example, the 5G communicationtechnologies, such as the sensor network, the M2M, and the MTC, havebeen implemented by techniques, such as the beamforming, the MIMO, andthe array antenna. The application of the cloud RAN as the big dataprocessing technology described above may also be considered as anexample of the fusing of the 5G communication technology with the IoTtechnology.

In accordance with the recent development of LTE and LTE-advanced, amethod of acquiring information on a beam that a user equipment (UE) ora base station may be used for signal transmission and reception in amobile communication system may be required.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea search procedure for searching for and determining information on abeam that a user equipment (UE) or a base station can use for signaltransmission and reception. The disclosure provides a process ofexchanging the searched beam information between the base station andthe UE and sharing information on a beam to be used for subsequenttransmission and reception.

Aspects of the disclosure are not limited to the above-mentionedaspects. For example, other aspects that are not mentioned may beobviously understood by those skilled in the art to which the disclosurepertains from the following description.

In accordance with an aspect of the disclosure, a method for beammanagement by a UE is provided. The method includes receiving, from abase station, channel state information reference signal (CSI-RS)resource information for beam management, the CSI-RS resourceinformation including a repetition indicator indicating whether a CSI-RSresource set is repeated in a time domain and transmitting, to the basestation, a beam report for the CSI-RS resource set based on the CSI-RSresource information.

According to the embodiment of the disclosure, the CSI-RS resourceinformation includes at least one of a synchronization sequence (SS)block index having quasi-co-location (QCL) relationship with the CSI-RSresource set, resource allocation information for the CSI-RS resourceset, and a transmission period for the CSI-RS resource set.

According to the embodiment of the disclosure, the CSI-RS resource setin a symbol is repeated across N symbols when the repetition indicatoris set to a first value, and the CSI-RS resource set is located in adesignated symbol when the repetition indicator is set to a secondvalue.

According to the embodiment of the disclosure, the method furthercomprises selecting a beam to receive the CSI-RS resource set when therepetition indicator is set to the first value.

According to the embodiment of the disclosure, the CSI-RS resourceinformation is received via one of master information block (MIB),system information block (SIB), and radio resource control (RRC)message.

In accordance with another aspect of the disclosure, a method for beammanagement by a base station is provided. The method includestransmitting, to a UE, CSI-RS resource information for beam management,the CSI-RS resource information including a repetition indicatorindicating whether a CSI-RS resource set is repeated in a time domainand receiving, from the UE, a beam report for the CSI-RS resource setbased on the CSI-RS resource information.

According to the embodiment of the disclosure, the CSI-RS resourceinformation includes at least one of a SS block index having QCLrelationship with the CSI-RS resource set, resource allocationinformation for the CSI-RS resource set, and a transmission period forthe CSI-RS resource set.

According to the embodiment of the disclosure, the CSI-RS resource setin a symbol is repeated across N symbols when the repetition indicatoris set to a first value, and the CSI-RS resource set is located in adesignated symbol when the repetition indicator is set to a secondvalue.

According to the embodiment of the disclosure, a beam to receive theCSI-RS resource set is selected when the repetition indicator is set tothe first value.

According to the embodiment of the disclosure, the CSI-RS resourceinformation is transmitted via one of MIB, SIB, and RRC message.

In accordance with another aspect of the disclosure, a UE for performingbeam management is provided. The UE includes a transceiver and at leastone processor coupled with the transceiver and configured to control toreceive, from a base station, CSI-RS resource information for beammanagement, the CSI-RS resource information including a repetitionindicator indicating whether a CSI-RS resource set is repeated in a timedomain and transmit, to the base station, a beam report for the CSI-RSresource set based on the CSI-RS resource information.

In accordance with another aspect of the disclosure, a base station forperforming beam management is provided. The base station includes atransceiver and at least one processor coupled with the transceiver andconfigured to control to transmit, to a UE, CSI-RS resource informationfor beam management, the CSI-RS resource information including arepetition indicator indicating whether a CSI-RS resource set isrepeated in a time domain and receive, from the UE, a beam report forthe CSI-RS resource set based on the CSI-RS resource information.

According to an embodiment of the disclosure, it is assumed that thedisclosure is based on a two-layer beam configuration. The first layerbeam referred in the disclosure refers to the base station beam used totransmit the SS blocks. The first layer beam may be used for control anddata transmission until the search for the second layer beam iscompleted. Hereinafter, the beam searching and setting procedure for thefirst layer will be referred to as the P1 beam management (P1 BM)operation. The second layer beam referred in the disclosure refers tothe base station beam used for control and data transmission.Hereinafter, the beam searching and setting procedure for the secondlayer will be referred to as the P2 beam management (P2 BM) operation.The disclosure proposes the method of operating a base station/UE forsupporting P1 and P2 procedures and the method of allocating CSI-RS forbeam search.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram illustrating an overall operation according to anembodiment of the disclosure;

FIGS. 2A and 2B are diagrams illustrating a first embodiment (when acell-specific reference signal (RS) is not allocated) for performing abeam searching and setting procedure according to various embodiments ofthe disclosure;

FIGS. 3A and 3B are diagrams illustrating a second embodiment (when acell-specific RS is allocated) for performing a beam searching andsetting procedure according to various embodiments of the disclosure;

FIG. 4 is a diagram illustrating a quasi-co-location (QCL) relationshipbetween a synchronization sequence (SS) block and a first channel stateinformation RS (CSI-RS) (=Cell-specific RS) according to an embodimentof the disclosure;

FIG. 5 is a diagram illustrating an embodiment of a method ofconfiguring a first CSI-RS (=Cell-specific RS) according to anembodiment of the disclosure;

FIG. 6 is a diagram illustrating an embodiment (tracking RS support) ofthe method of configuring a first CSI-RS (=Cell-specific RS) accordingto an embodiment of the disclosure;

FIGS. 7A and 7B are diagrams illustrating an embodiment (tracking RSsupport) of a method of configuring a first CSI-RS (support of twoantenna ports) according to various embodiments of the disclosure;

FIG. 8 is a diagram illustrating a configuration of a base stationaccording to an embodiment of the disclosure;

FIG. 9 is a diagram illustrating a configuration of a terminal accordingto an embodiment of the disclosure;

FIG. 10 is a diagram illustrating a resource element (RE) mappingpattern of CSI-RS resources according to an embodiment of thedisclosure;

FIGS. 11A, 11B, and 11C are diagrams illustrating a process oftransmitting an SS-block and CSI-RS resource sets according to variousembodiments of the disclosure;

FIG. 12 is a diagram illustrating an embodiment of an RE mapping patternof CSI-RS according to an embodiment of the disclosure;

FIG. 13 is a diagram illustrating an embodiment of an RE mapping patternof a CSI-RS according to an embodiment of the disclosure;

FIG. 14 is a diagram illustrating an embodiment of an RE mapping patternof a CSI-RS according to an embodiment of the disclosure;

FIG. 15 is a diagram illustrating mapping of one CSI-RS for each two Resaccording to an embodiment of the disclosure;

FIG. 16 is a diagram illustrating an embodiment that may be used onlyfor P1 beam management (P1 BM) without tracking RS support according toan embodiment of the disclosure;

FIG. 17 is a diagram illustrating an embodiment that may be used onlyfor P1 BM without a tracking RS support according to an embodiment ofthe disclosure;

FIG. 18 is a diagram illustrating an embodiment that supportstime-domain repetition according to an embodiment of the disclosure;

FIG. 19 is a diagram illustrating an RE mapping pattern of a CSI-RS, inwhich a case in which code division multiplexing (CDM) is not appliedbetween resources is illustrated according to an embodiment of thedisclosure;

FIG. 20 is a diagram illustrating an RE mapping pattern of a CSI-RS, inwhich a case in which a CDM is applied between resources is illustratedaccording to an embodiment of the disclosure;

FIG. 21 is a diagram illustrating an RE mapping pattern of a CSI-RS, andillustrates a case in which CDM is not applied between resourcesaccording to an embodiment of the disclosure;

FIG. 22 is a diagram illustrating an embodiment defining severalresource sets in one orthogonal frequency division multiplexing (OFDM)symbol according to an embodiment of the disclosure;

FIG. 23 is a diagram illustrating an embodiment defining severalresource sets in one OFDM symbol according to an embodiment of thedisclosure;

FIGS. 24, 25, 26, 27, 28, and 29 are diagrams illustrating a resourceindex and a resource set index of a CSI-RS transmitted in one slotaccording to various embodiments of the disclosure;

FIG. 30 is a diagram illustrating a process of performing resourcesetting having an index of S1, S2, . . . , SN according to an embodimentof the disclosure;

FIG. 31 is a diagram illustrating QCL information between K1 CSI-RSresources for P1 BM and K2 resources for P2 BM according to anembodiment of the disclosure;

FIG. 32 is a diagram illustrating a CSI-RS resource setting between abase station and a terminal according to an embodiment of thedisclosure;

FIG. 33 is a diagram illustrating a case in which K CSI-RS resources (orport groups) are allocated to one OFDM symbol according to an embodimentof the disclosure;

FIG. 34 is a diagram illustrating a case in which one resource or a portgroup is mapped to NP×L Res according to an embodiment of thedisclosure;

FIG. 35 is a diagram illustrating an embodiment of a case in which tworesource groups are set in one OFDM symbol according to an embodiment ofthe disclosure; and

FIG. 36 is a diagram illustrating a case in which L=4 sub-time unit OFDMsymbols are generated within one OFDM symbol interval according to anembodiment of the disclosure.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to those ofskill in the art, may occur in amounts that do not preclude the effectthe characteristic was intended to provide.

Various advantages and features of the disclosure and methodsaccomplishing the same will become apparent from the following detaileddescription of embodiments with reference to the accompanying drawings.However, the disclosure is not limited to the embodiments disclosedherein but will be implemented in various forms. The embodiments havemade disclosure of the disclosure complete and are provided so thatthose skilled in the art can easily understand the scope of thedisclosure. Therefore, the disclosure will be defined by the scope ofthe appended claims. Like reference numerals throughout the descriptiondenote like elements.

First Embodiment: Method of Operating P3 Procedure Based onSynchronization Sequence (SS) Block Index Reporting

The disclosure assumes a two-layer beam configuration as a basis. Thefirst layer beam referred in the disclosure refers to the base stationbeam used to transmit the SS blocks. The first layer beam may be usedfor control and data transmission until the search for the second layerbeam is completed. Hereinafter, the procedure of searching for andsetting the beam for the first layer will be referred to as the P1 beammanagement (P1 BM) operation. The second layer beam referred in thedisclosure refers to the base station beam used for control and datatransmission. Hereinafter, the beam searching and setting procedure forthe second layer will be referred to as the P2 beam management (P2 BM)operation.

Meanwhile, a P3 beam management (P3 BM) operation referred to in thedisclosure refers to a process of supporting a search for a terminalbeam.

FIG. 1 is a diagram illustrating an overall operation according to anembodiment of the disclosure.

Referring to FIG. 1, upon an initial access, a base station 100 and auser equipment (UE) 110 complete the searching and setting of the beamthat may be used for signal transmission and reception between the basestation 100 and the UE 110. The beam corresponds to a beam belonging tothe first layer. The configuration for the beam set upon the initialaccess may be updated to the setting of the beam belonging to the secondlayer while an additional beam setting procedure is performed duringdata transmission after the initial access.

In this case, the search for the beam means a process of searching forand determining information on beams that the UE 110 or the base station100 can use for signal transmission and reception. Meanwhile, thesetting of the beam refers to a process of exchanging the searched beaminformation between the base station 100 and the UE 110 and sharinginformation on a beam to be used for subsequent transmission andreception.

The disclosure provides two representative embodiments for performingthe beam searching and setting procedure. On the other hand, it may bedetermined whether to operate according to the first embodiment or thesecond embodiment depending on according to whether the followingcell-specific reference signal (RS) is allocated. For example, when thecell-specific RS is not allocated, the base station/terminal may beoperated as in the first embodiment. Meanwhile, when the cell-specificRS is not allocated, the base station/terminal may be operated as in thesecond embodiment. Meanwhile, it may be determined whether to operateaccording to the first embodiment or to operate according to the secondembodiment depending on the determined of the base station. For example,the base station may notify the terminal of the setting of whether toperform a BM operation based on any of the two embodiments.

FIGS. 2A and 2B are diagrams illustrating a first embodiment (when acell-specific RS is not allocated) for performing a beam searching andsetting procedure according to various embodiments of the disclosure.

Referring to FIG. 2A, at this time, a UE 210 receives a Synch signalconsisting of SS blocks for performing a P1 procedure from a basestation 200. The UE 210 determines a preferred best SS block index basedon the received Synch signal and feeds back the determined best SS blockindex to the base station 200. At this time, the UE 210 can select an Lvalue which is a value corresponding to the number of terminal receptionbeams used to receive the best SS block index. The number of best SSblock index to be fed back to the base station 200 may be one or more,and the base station may set the number of best indexes to be fed backin the terminal.

Referring to FIG. 2B, in the following P2 and P3 processes, the beamsearch is performed by allocating UE-specific RS. The base station 200selects K base station beams to be used for the P2 and P3 proceduresbased on the best SS block index information that the UE 210 feed backs.Then, the UE-specific RS consisting of K base station beams isallocated, so that the UE 210 may select the best N base station beams.At this time, the UE-specific RS may be repeatedly transmitted L timeson a time base based on the number of terminal beams L. In order toefficiently perform such repetitive transmission, the UE-specific RS mayhave an orthogonal frequency division multiplexing (OFDM) symbol lengthshorter than an OFDM symbol length used for general data transmission.The OFDM symbol length having the short length is named a sub-time unitin FIGS. 2A and 2B.

The UE 210 receives each channel state information RS (CSI-RS) resourceset using L terminal beams in each sub-time unit. The UE 210 selects Nresource sets, selects a corresponding UE beam for each selectedresource set, and generates a corresponding precoding matrix indicator(PMI)/rank indicator (RI)/channel quality indicator (CQI) report foreach selected resource set. Then, the UE 210 reports multiple input andmultiple output (MIMO) reporting (N resource index, UE beam set indexcorresponding to each resource, PMI/RI/CQI corresponding to eachresource) to the base station 200.

Second Embodiment: Method of Operating P3 Procedure Based on P-CSI-RSHaving a Quasi-Co-Location (QCL) Relationship with SS Block

FIGS. 3A and 3B are diagrams illustrating a second embodiment (when acell-specific RS is allocated) for performing a beam searching andsetting procedure according to various embodiments of the disclosure.

Referring to FIGS. 3A and 3B, a base station 300 provides Rx beam QCLrelationship information between the Synch signal and the cell-specificRS to the UE 310 and transmits a Synch signal (composed of M SS blocks)to the UE 310. The UE 310 measures the strength of the received signalstrength of each UE and selects L corresponding terminal beams for eachSS block index. The base station 300 transmits the cell-specific RS(Consisting of M resource sets) to perform the P1 procedure.

The UE 310 receives a resource set having a QCL relationship using thecell-specific RS with one terminal beam out of L, performs measurementon the base station beam through the reception of the cell-specific RSand performs a BM report upon the request of the base station 300. Whenthe base station 300 requests the BM report to the UE 310, the basestation 300 may indicate the following K value to the UE 310. At thistime, the BM report may include information indicating K base stationbeam indexes and received signal strength information of the K beams. Inaddition, for the K base station beams, the terminal can also report UEbeam set index information together.

For K′ beams reported to the base station 300 having the same UE beamset index among the K base station beams, the base station 300 assumesthat the UE 310 can receive a signal using the same terminal beam. Thebase station 300 receiving the BM report including the UE beam set indexmay simultaneously use beams corresponding to a base station beam IDshaving the same set index to transmit and receive signals to and fromthe UE 310. Alternatively, to transmit and receive a signal to and fromthe terminal, the base station may alternately use the base stationbeams corresponding to the base station beam IDs having the same setindex without notifying the terminal in advance. The cell-specific RSfor the P1 BM operation may be replaced with the UE-specific RS for theP1 BM according to the determination of the base station and set.

Third Embodiment: CSI-RS Resource Setting Method for Beam Management

Hereinafter, a CSI-RS resource setting method according to thedisclosure will be described. The disclosure includes three types ofCSI-RS resource setting methods each of which is referred to as “P1 BMand tracking RS,” “P2 and P3 BM,” and “P2 BM and MIMO CSI”.

The first type of CSI-RS means the cell-specific RS referred to in thebeam searching and setting method. The first type of CSI-RS maybe usedfor the P1 BM and the Tracking RS. This means that the CSI-RS allocationof the first method may be established based on system information block(SIB) or radio resource control (RRC). On the other hand, the first typeof CSI-RS used for the P1 BM and the Tracking RS may not be allocatedaccording to the selection of the base station. The base station mayindicate to the terminal whether the first type of CSI-RS is allocatedin master information block (MIB).

The following Table 1 shows specific parameters for setting the firsttype of CSI-RS. The CSI-RS is always set as periodic transmission.

TABLE 1 CSI-RS resource setting  Type: BM P1  Set index: m′  QCL info:SS block index m  Resource setting: Slot & Symbol-level  Number ofresources per symbol: {2, 4, 8, 16, 32, 64}  Number of antenna ports perresource: {1, 2}  Sub-time unit order (L): {1, 2, 4} if L > 1,  Time-domain repetition distance (D): D = {0, 4}    If D = 0, norepetition is applied    If D = 4, time-domain repetition is applied  Txperiod: {5 ms, 10 ms, 15 ms, 20 ms} periodic  Subcarrier spacing: {60KHz, 120 KHz, 240 KHz}

The following various embodiments are possible depending on the specificparameter values used for the first type of CSI-RS setting.

The following Table 2 is an embodiment that may be used only for the P1BM without Tracking RS support. The specific CSI-RS allocation resultsaccording to the following embodiment are illustrated in FIGS. 4 and 5.

FIG. 4 is a diagram illustrating a QCL relationship between an SS blockand a first CSI-RS (=Cell-specific RS) according to an embodiment of thedisclosure.

FIG. 5 is a diagram illustrating an embodiment of a method ofconfiguring a first CSI-RS (=Cell-specific RS) according to anembodiment of the disclosure.

Referring to FIG. 4, CSI-RS resource sets 0, 1, 2, and 3 each have a QCLrelationship with SS block indexes 0, 1, 2, and 3. At this time, itmeans that at least one terminal beam of the L terminal beams searchedin the SS block having the QCL relationship may be used in the CSI-RShaving the QCL relationship.

Referring to FIG. 5, since two OFDM symbols are used in each resourceset and 8 resources are set per symbol, a total of 16 CSI-RS resourcesare repeatedly allocated on a frequency base in one resource asillustrated in FIG. 5. Since a total of 4 resource sets are set, so thata total of 64 CSI-RS resources may be set in the terminal through thesetting as illustrated in the following Table 2.

TABLE 2 Common parameters Number of symbols per resource set: 2 Numberof resources per symbol: 8 Number of antenna ports per resource:1Sub-time unit order (L): 1 Tx period: 10 ms Subcarrier spacing: 60 KHzSet specific parameters Set index: 0 Set index: 2 Qainfo: SS block index0 QCL info: SS block index 2 Resource setting: 10^(th) slot and5^(th)-6^(th) Resource setting: 10^(th) slot and symbol 9^(th)-10^(th)symbol Set index: 1 Set index: 3 QCL info: SS block index 1 QCL info: SSblock index 3 Resource setting: 10^(th) slot and 7^(th)-8^(th) Resourcesetting: 10^(th) slot and symbol 11^(th)-12^(th) symbol

The following Table 3 shows an embodiment supporting the Tracking RS.The specific CSI-RS allocation results according to the followingembodiment are illustrated in FIG. 6.

FIG. 6 is a diagram illustrating an embodiment (tracking RS support) ofthe method of configuring a first CSI-RS (=Cell-specific RS) accordingto an embodiment of the disclosure.

Referring to FIG. 6, since the number of resources per symbol is 4 and atotal of 4 symbols are allocated in one resource set (number of symbolsper resource set 2×sub-time unit order 2=4), a total of 16 CSI-RSresources are allocated in one resource set. Meanwhile, since atime-domain repetition distance is allocated as D=4, as illustrated inFIG. 6, the CSI-RS resources corresponding to the corresponding resourceset are repeatedly allocated to a location separated by 4 symbols basedon sub-carrier spacing 60 KHz.

TABLE 3 Common parameters  Number of symbols per resource set: 2  Numberof resources per symbol: 4  Number of antenna ports per resource: 1 Sub-time unit order (L): 2  Time-domain repetition distance (D symbolsapart): D = 4  Tx period: 10 ms  Subcarrier spacing: 60 KHz Set specificparameters  Set index: 0   QCL info: SS block index 0   Resourcesetting: 10^(th) slot and 5^(th)-6^(th) symbol  Set index: 1   QCL info:SS block index 1   Resource setting: 10^(th) slot and 7^(th)-8^(th)symbol

The following Table 4 illustrates an embodiment supporting two antennaports. The specific CSI-RS allocation results according to the presentembodiment are illustrated in FIGS. 7A and 7B.

FIGS. 7A and 7B are diagrams illustrating an embodiment (tracking RSsupport) of the method of configuring a first CSI-RS (support of twoantenna ports) according to various embodiments of the disclosure.

Referring to FIGS. 7A and 7B, unlike the previous embodiment of thedisclosure, one CSI-RS resource having two antenna ports is allocated totwo neighboring REs on a frequency axis.

TABLE 4 Common parameters  Number of symbols per resource set: 2  Numberof resources per symbol: 4  Number of antenna ports per resource: 2 Sub-time unit order (L): 2  Time-domain repetition distance (D symbolsapart): D = 0  Tx period: 10 ms  Subcarrier spacing: 60 KHz Set specificparameters  Set index: 0   QCL info: SS block index 0   Resourcesetting: 10^(th) slot and 5^(th)-6^(th) symbol  Set index: 1   QCL info:SS block index 1   Resource setting: 10^(th) slot and 7^(th)-8^(th)symbol

The second type of CSI-RS may be used for P2 BM and P3 BM. This may bedistinguished from the first type of CSI-RS allocation method in termsof the following aspects.

-   -   Periodic or aperiodic        -   Sub-time unit order (L) is dynamically indicated by DCI for            aperiodic transmission        -   Sub-time unit order (L) is configured by RRC or MAC CE for            aperiodic transmission    -   UE-specifically configured by RRC or MAC CE    -   If sub-time unit is triggered, same resource ID between sub-time        units on the same RE position. (for P3 support)    -   Time-domain repetition with D symbols apart is not supported        (i.e., no CFO tracking support)    -   QCL association with CSI-RS for P1 BM        -   If CSI-RS for P1 BM is not configured, then this association            is applied to SS blocks.

The third type of CSI-RS may be used for the P2 BM and the MIMO CSI.This may use the same method as the method of allocating CSI-RS used infull dimensional MIMO (FD-MIMO) of the existing long-term evolution(LTE).

FIG. 8 is a diagram illustrating a configuration of a base stationaccording to an embodiment of the disclosure.

Referring to FIG. 8, a base station processor 810 according to anembodiment of the disclosure may perform the beam searching and settingprocedure using information transmitted and received through a basestation receiver 820 and a base station transmitter 830. The basestation processor 810 may control the base station receiver 820 and thebase station transmitter 830 and may perform the base station operationaccording to the embodiments of the disclosure.

FIG. 9 is a diagram illustrating a configuration of a terminal accordingto an embodiment of the disclosure.

Referring to FIG. 9, a terminal processor 910 according to an embodimentof the disclosure may perform the beam searching and setting procedureusing information transmitted and received through a terminal receiver920 and a terminal transmitter 930. The terminal processor 910 maycontrol the terminal receiver 920 and the terminal transmitter 930 andmay perform the terminal operation according to the embodiments of thedisclosure.

Hereinafter, another CSI-RS resource setting method according to thedisclosure will be described, and this CSI-RS may be used for P1, P2,and P3 BM referred to in the beam searching and setting method. The basestation may transmit the setting of the CSI-RS to the terminal throughthe MIB, the SIB, or the RRC. Meanwhile, the CSI-RS may not be allocatedaccording to the selection of the base station, and the base station mayindicate to the terminal whether the CSI-RS is allocated in the MIB orthe SIB.

The following Table 5 shows specific parameters for setting the CSI-RS.The CSI-RS may be set as the periodic transmission or non-periodictransmission. Meanwhile, activation/deactivation of the CSI-RS may beset for each resource set. For example, the CSI-RS resource set as theactivation is periodically transmitted, and the transmission of theCSI-RS resource set as the deactivation is periodically stopped. If theterminal receives PDSCH scheduling in a slot including the CSI-RSresource set as the periodic transmission, the terminal may performdecoding under the assumption that the PDSCH is not allocated in theOFDM symbol including the CSI-RS resource.

TABLE 5 CSI-RS resource setting Type: Beam management Set index: m′ QCLinfo: SS block index m (or CSI-RS resource set index m) Resourceallocation: Slot index & Symbol index & Number of symbols (N)Time-domain repetition indicator: {1, 0} If repetition is activated, aresource set in one OFDM symbol is repeated across N symbols Ifrepetition is not activated, N × K resources are defined in a resourceset within N symbols Number of resources per symbol (K): {2, 4, 8}Alt 1) CDM-K among resources Alt 2) no CDM between resources Number ofantenna ports per resource: {1, 2} Alt 1) CDM-2 between antenna ports(if P = 2) Alt 2) no CDM between antenna ports Sub-carrier spacing(f_s): {60, 120, 240 KHz} Sub-time unit order (L): {1, 2, 4} Tx period:{5, 10, 15, 20 ms} periodic Density reduction parameter: Gap = { },Shift value = { } Alt 1) Gap between ports Alt 2) Gap between resourcesAlt 3) Gap between resource groups

The following Table 6 shows a configuration example for CSI-RS resourceset No. 0 having the QCL relationship with SS block index No. 0. Theresource set is located in a 5-th symbol in a 10-th slot. At this time,the slot index follows criteria defined in reference numerology signaledin the MIB. For example, assuming that the reference numerology is 60KHz, a total of 40 slots may be defined within a 10 ms radio frame(assuming a length of 0.25 ms per slot). Meanwhile, assuming that thereference numerology is 120 KHz, a total of 80 slots may be definedwithin the 10 ms radio frame (assuming a length of 0.125 ms per slot).The resource set is transmitted in the 5-th symbol based on the symbolindex reference defined by f_s KHz in the slot. For example, if thereference numerology is 60 KHz or 120 KHz, a total of 56 or 28 definedby f_s=240 KHz symbols are included in one slot.

The sub-time unit order (L) is a parameter indicating how manysub-symbols the one symbol consists of. In the case of L=1, one symbolmay not consist of sub-symbols. In the case of L>1, one symbol mayconsist of L sub-symbols using an interleaved frequency divisionmultiple access (IFDMA) scheme. At this time, the same transmissionsignal is repeatedly transmitted between the sub-symbols, and the basestation beam is kept unchanged among the sub-symbols.

The time-domain repetition indicator is a parameter indicating whetherthe symbol is repeated at the symbol level in the time domain. Forexample, when this value is set to be 0, the resource set is locatedonly in the 5-th symbol in the 10-th slot. The indicator value may beset to be 1 only if an N value is greater than 1, and if the N value isset to be 1, the resource set defined in one OFDM symbol is repeatedlytransmitted over N symbols.

The resource set is repeatedly transmitted with a transmission period of“10 ms”.

The density reduction parameter is a value set so that the resource setcan use only a part of resources in the symbol defined by the f_s KHz.Since gap=0 RE, the present example is an example in which the densityreduction function is not supported.

TABLE 6 CSI-RS resource setting Type: Beam management Set index: 0 QCLinfo: SS block index 0 Resource allocation: 10-th Slot, 5-th Symbol, N =1 Time-domain repetition indicator: 0 Number of resources per symbol(K): 4 Number of antenna ports per resource: 2 Sub-carrier spacing(f_s): 240 KHz Sub-time unit order (L): 1 Tx period: 10 ms periodicDensity reduction parameter: Gap = 0 REs, Shift value = 0-th RE

The resource element (RE) mapping pattern of the specific CSI-RSresources shown in the above Table 6 is illustrated in FIG. 10.

FIG. 10 is a diagram illustrating an RE mapping pattern of CSI-RSresources according to an embodiment of the disclosure.

Referring to FIG. 10, the code division multiplexing (CDM) is notapplied. As illustrated in FIG. 10, the RE mapping pattern of the KCSI-RS resources is repeatedly shown while being FDMed within theconfigured CSI-RS BW.

FIGS. 11A, 11B, and 11C are diagrams illustrating a process oftransmitting an SS-block and CSI-RS resource sets according to variousembodiments of the disclosure.

Referring to FIGS. 11A, 11B, and IC, in addition to CSI-RS resource set0 having the QCL relationship with SS block index 0, if the CSI-RSresource sets 1, 2, and 3 having the QCL relationship with the SS blockindexes 1, 2, and 3 are configured in symbol indexes 6, 7, and 8 in thesame 10-th slot, SS-block and CSI-RS resource sets may be transmitted asillustrated in FIG. 11A. Here, the SS-block and the CSI-RS resource setindicated by the same color have the same QCL relationship. It isassumed that the same base station beam is used for transmission in theSS-block and the CSI-RS resource set having the QCL relationshipassociated with each other.

Referring to FIG. 11B, CSI-RS resource sets 0, 1, 2 and 3 having a QCLrelationship with the SS block index 0, 1, 2 and 3 are transmitted basedon the configured CSI-RS BW and a predetermined symbol position (basedon the time-unit length set based on the f_s value). Referring to FIG.11C, CSI-RS resource sets may be transmitted through predetermined basestation beams determined based on a CSI-RS resource set, a resourceindex (CSI-RS), and a port index.

In addition, one SS-block may have the QCL relationship with severalCSI-RS resource sets. The terminal may search for a terminal beamsuitable for reception of the CSI-RS resources associated with theSS-block based on SS-block received signal strength.

The following Table 7 is an example of defining two resource sets byusing the density reduction parameters, in which “Alt 3) gap betweenresource groups” is set by density reduction method. The RE mappingpattern of the CSI-RS as shown in the following Table 7 is illustratedin FIG. 12.

FIG. 12 is a diagram illustrating an embodiment of an RE mapping patternof CSI-RS according to an embodiment of the disclosure.

Referring to FIG. 12, the two sets are each configured at the sameslot/symbol location, and the gap and the shift value are set to be 8REs, which is occupied by one resource group, in order to avoid overlapbetween the resource groups belonging to different sets.

TABLE 7 CSI-RS resource setting (Common part) - Type: Beam management -QCL info: SS block index 0 - Resource allocation: 10-th Slot, 5-thSymbol, N = 1 - Time-domain repetition indicator: 0 - Number ofresources per symbol (K): 4 - Number of antenna ports per resource: 2 -Sub-carrier spacing (f_s): 240 KHz - Sub-time unit order (L): 1 - Txperiod: 10 ms periodic - Density reduction parameter: Gap = 8 REs ′-“Alt-3” is configured for density reduction method CSI-RS resourcesetting (Set-specific part) - Set index: 0 - Density reductionparameter: Shift value = 0-th RE - Set index: 1 - Density reductionparameter: Shift value = 8-th RE

For example, the following Table 8 shows an example in which fourresource sets are defined in one symbol using the density reductionparameters, and the RE mapping pattern of the corresponding CSI-RS isillustrated in FIG. 13.

FIG. 13 is a diagram illustrating an embodiment of an RE mapping patternof the CSI-RS according to an embodiment of the disclosure.

TABLE 8 CSI-RS resource setting (Common part) - Type: Beam management -QCL info: SS block index 0 - Resource allocation: 10-th Slot, 5-thSymbol, N = 1 - Time-domain repetition indicator: 0 - Number ofresources per symbol (K): 4 - Number of antenna ports per resource: 2 -Sub-carrier spacing (f_s): 240 KHz - Sub-time unit order (L): 1 - Txperiod: 10 ms periodic - Density reduction parameter: Gap = 32 REs ′-“Alt-3” is configured for density reduction method CSI-RS resourcesetting (Set-specific part) - Set index: 0 - Density reductionparameter: Shift value = 0-th RE - Set index: 1 - Density reductionparameter: Shift value = 8-th RE - Set index: 2 - Density reductionparameter: Shift value = 16-th RE - Set index: 3 - Density reductionparameter: Shift value = 24-th RE

Referring to FIG. 13, for example, the following Table 9 is an examplein which two resource sets are defined in one symbol by using thedensity reduction parameter. At this time, “Alt-2” which defines the gapbetween resources is used. In this case, to avoid the overlap betweenthe resources belonging to the two sets, the RE number of resourcesoccupied by one resource is 2, which is set for the gap and the shiftvalue. The RE mapping pattern of the corresponding CSI-RS is illustratedin FIG. 14.

FIG. 14 is a diagram illustrating an embodiment of an RE mapping patternof a CSI-RS according to an embodiment of the disclosure.

TABLE 9 CSI-RS resource setting (Common part) - Type: Beam management -QCL info: SS block index 0 - Resource allocation: 10-th Slot, 5-thSymbol, N = 1 - Time-domain repetition indicator: 0 - Number ofresources per symbol (K): 4 - Number of antenna ports per resource: 2 -Sub-carrier spacing (f_s): 240 KHz - Sub-time unit order (L): 1 - Txperiod: 10 ms periodic - Density reduction parameter: Gap = 2 REs ′-“Alt-2” is configured for density reduction method CSI-RS resourcesetting (Set-specific part) - Set index: 0 - Density reductionparameter: Shift value = 0-th RE - Set index: 1 - Density reductionparameter: Shift value = 2-th RE

Referring to FIG. 14, several resource sets may be transmitted whilebeing mapped to one OFDM symbol using the above-described densityreduction method. The resource set may be used for the CSI-RSstransmitted in different total radiated powers (TRPs). The NW may be setin the terminal to activate measurement and reporting only for someresource sets. In addition, the NW may be set in the terminal toactivate the measurement and reporting on the resource set having theQCL relationship with the corresponding SS-block index based on theSS-block index received from the terminal.

The following Table 10 shows the sub-time unit setting method. If thesub-time unit order (L) value is set, the RE for the CSI-RS is mapped atintervals of L×f_s using the IFDMA method.

FIG. 15 is a diagram illustrating mapping of one CSI-RS for each two REsaccording to an embodiment of the disclosure.

Referring to FIG. 15, for example, when L=2 and f_s=120 KHz, asillustrated in FIG. 15, one Cs-RS is mapped to each two REs. At thistime, one RE has a size of 120 KHz. As described above, one time-unitlength is defined by “ 1/120 ms” based on the set f_s value. A time-axissignal repeated L times in the time-unit is observed. The terminal mayperform Rx beam sweeping up to L times within the time-unit. Thesub-time unit order (L) value may be more dynamically signaled throughthe MAC CE.

TABLE 10 CSI-RS resource setting Type: Beam management Set index: 0 QCLinfo: SS block index 0 Resource allocation: 10-th Slot, 5-th Symbol, N =1 Time-domain repetition indicator: 0 Number of resources per symbol(K): 4 Number of antenna ports per resource: 2 Sub-carrier spacing(f_s): 120 KHz Sub-time unit order (L): 2 Tx period: 10 ms periodicDensity reduction parameter: Gap = 0 REs, Shift value = 0-th RE

The following Table 11 is an example that may be used only for the P1 BMwithout Tracking RS support. The specific CSI-RS allocation resultsaccording to the following embodiment are illustrated in FIGS. 16 and17.

FIG. 16 is a diagram illustrating an embodiment that may be used onlyfor P1 BM without tracking RS support according to an embodiment of thedisclosure.

FIG. 17 is a diagram illustrating an embodiment that may be used onlyfor P1 BM without a tracking RS support according to an embodiment ofthe disclosure.

Referring to FIG. 16, the CSI-RS resource sets 0, 1, 2, and 3 each havea QCL relationship with the SS block indexes 0, 1, 2, and 3. At thistime, it means that at least one terminal beam of the L terminal beamssearched in the SS block having the QCL relationship may be used in theCSI-RS having the QCL relationship.

Referring to FIG. 17, in addition, since two OFDM symbols are used ineach resource set and 8 resources are set per symbol, a total of 16CSI-RS resources are repeatedly allocated on the frequency base in oneresource as illustrated in FIG. 17. Since a total of 4 resource sets areset, so that a total of 64 CSI-RS resources may be set in the terminalthrough the setting as illustrated in the following Table 11.

TABLE 11 CSI-RS resource setting (Common part) Type: Beam managementTime-domain repetition indicator: 0 Number of resources per symbol (K):8 Number of antenna ports per resource: 1 Sub-carrier spacing (f_s): 240KHz Sub-time unit order (L): 1 Tx period: 10 ms periodic Densityreduction parameter: Gap = 0 REs, Shift value = 0-th RE CSI-RS resourcesetting (Set-specific part) Set index: 0 QCL info: SS block index 0Resource allocation: 10-th Slot, 5-th Symbol, N = 2 Set index: 1 QCLinfo: SS block index 1 Resource allocation: 10-th Slot, 7-th Symbol, N =2 Set index: 2 QCL info: SS block index 2 Resource allocation: 10-thSlot, 9-th Symbol, N = 2 Set index: 3 QCL info: SS block index 3Resource allocation: 10-th Slot, 11-th Symbol, N = 2

The following Table 12 shows an embodiment supporting time-domainrepetition. The specific CSI-RS allocation results according to thefollowing embodiment are illustrated in FIG. 18.

FIG. 18 is a diagram illustrating an embodiment that supportstime-domain repetition according to an embodiment of the disclosure.

Referring to FIG. 18, since the time-domain repetition indicator valueis set to be 1, as shown in FIG. 18, the resource set defined in oneOFDM symbol based on the sub-carrier spacing (f_s) 240 KHz is repeatedlytransmitted over N symbols. For example, the base station transmits thesame resource set N times using the same Tx beam over N symbols, and theterminal may perform an Rx beam sweeping (P3 BM) operation correspondingto a maximum of N×L times.

TABLE 12 CSI-RS resource setting (Common part) Type: Beam managementTime-domain repetition indicator: 1 Number of resources per symbol (K):8 Number of antenna ports per resource: 1 Sub-carrier spacing (f_s): 240KHz Sub-time unit order (L): 1 Tx period: 10 ms periodic Densityreduction parameter: Gap = 0 REs, Shift value = 0-th RE CSI-RS resourcesetting (Set-specific part) Set index: 0 QCL info: SS block index 0Resource allocation: 10-th Slot, 5-th Symbol, N = 2 Set index: 1 QCLinfo : SS block index 1 Resource allocation: 10-th Slot, 7-th Symbol, N= 2 Set index: 2 QCL info : SS block index 2 Resource allocation: 10-thSlot, 9-th Symbol, N = 2 Set index: 3 QCL info: SS block index 3Resource allocation: 10-th Slot, 11-th Symbol, N = 2

FIG. 19 is a diagram illustrating an RE mapping pattern of a CSI-RS asshown in the following Table 13, in which a case in which the CDM is notapplied between resources is illustrated according to an embodiment ofthe disclosure.

Referring to FIG. 19, on the other hand, when P=2, the following signalsare applied to two REs allocated to one resource depending on whetherthe CDM is applied between the antenna ports.

-   -   X_(k)=[x_(k); 0], Y_(k)=[0; y_(k)] are applied if CDM between        antenna ports is not applied.    -   X_(k)=[x_(k); x_(k)], Y_(k)=[y_(k); −y_(k)] are applied if CDM        between antenna ports is applied.

The method of generating X_(k) and Y_(k) signals according to whetherthe CDM is applied between the antenna ports is similarly applied to thefollowing embodiments and FIGS. 19 to 23.

TABLE 13 CSI-RS resource setting Type: Beam management Set index: 0 QCLinfo: SS block index 0 Resource allocation: ( )-th Slot, ( )-th Symbol,N = 1 Time-domain repetition indicator: 0 Number of resources per symbol(K): 4 CDM between K resources is not applied Number of antenna portsper resource (P): 2 Sub-carrier spacing (f_s): 240 KHz Sub-time unitorder (L): 1 Tx period: 10 ms periodic Density reduction parameter: Gap= 0 REs, Shift value = 0-th RE

FIG. 20 is a diagram illustrating an RE mapping pattern of a CSI-RS, inwhich a case in which a CDM is applied between resources is illustratedaccording to an embodiment of the disclosure.

Referring to FIG. 20, an RE mapping pattern of a CSI-RS is illustratedin the following Table 14, in which a case in which a CDM is appliedbetween resources.

When the CDM is applied, one resource is mapped over 2K REs, and thetransmission signal X_(k) of antenna port No. 0 and the transmissionsignal Y_(k) of antenna port No. 1 for the k-th resource are as follows.

X_(k)=[a_(k)X₀; b_(k)X₁; c_(k)X₂; d_(k)X₃;], Y_(k)=[a_(k)Y₀; b_(k)Y₁;c_(k)Y₂; d_(k)Y₃;]

[a₀; b₀; c₀; d₀]=[1; 1; 1; 1]

[a₁; b₁; c₁; d₁]=[1; −1; 1; −1]

[a₂; b₂; c₂; d₂]=[1; 1; −1; −1]

[a₃; b₃; c₃; d₃]=[1; −1; −1; 1]

TABLE 14 CSI-RS resource setting Type: Beam management Set index: 0 QCLinfo: SS block index 0 Resource allocation: ( )-th Slot, ( )-th Symbol,N = 1 Time-domain repetition indicator: 0 Number of resources per symbol(K): 4 CDM between K resources is applied Number of antenna ports perresource (P): 2 Sub-carrier spacing (f_s): 240 KHz Sub-time unit order(L): 1 Tx period: 10 ms periodic Density reduction parameter: Gap = 0REs, Shift value = 0-th RE

FIG. 21 is a diagram illustrating an RE mapping pattern of a CSI-RS, andillustrates a case in which CDM is not applied between resourcesaccording to an embodiment of the disclosure.

Referring to FIG. 21, an RE mapping pattern of a CSI-RS is illustratedin the following Table 15, in which a case in which the CDM is notapplied between resources. In FIG. 21, the RE index in which resourcesare mapped by the IFDM scheme when the L value is greater than 1.

TABLE 15 CSI-RS resource setting Type: Beam management Set index: 0 QCLinfo: SS block index 0 Resource allocation: ( )-th Slot, ( )-th Symbol,N Time-domain repetition indicator: 0 Number of resources per symbol(K): 4 CDM between K resources is not applied Number of antenna portsper resource (P): 2 Sub-carrier spacing (f_s): 240 KHz Sub-time unitorder (L): L> 1 Tx period: 10 ms periodic Density reduction parameter:Gap = 0 REs, Shift value = 0-th RE

FIGS. 22 and 23 illustrate an embodiment defining several resource setsin one OFDM symbol according to an embodiment of the disclosure.

Referring to FIG. 22, a case in which two resource sets are set in oneOFDM according to Table 16 is illustrated. For example, the k+1-thresource and the k-th resource belonging to the same set is subjected tothe RE mapping while being spaced by gap=2 REs. In addition, in order toavoid the RE mapping overlapping between different sets, they havedifferent RE mapping start indexes (=Shift values) for each set, andthese values are set differently for each set by the shift value. Ingeneral, when SFDM resource sets are set in one OFDM symbol,gap=P×(S_(FDM)−1) REs can be commonly set for all sets, and the shiftvalue may be set for each set as 0 RE, P REs, . . . , P (S_(FDM)−1) REs.

TABLE 16 CSI-RS resource setting Type: Beam management QCL info: SSblock index 0 Resource allocation: ( )-th Slot, ( )-th Symbol, N = 1Time-domain repetition indicator: 0 Number of resources per symbol (K):4 CDM between K resources is not applied Number of antenna ports perresource (P): 2 Sub-carrier spacing (f_s): 240 KHz Sub-time unit order(L): 1 Tx period: 10 ms periodic Density reduction method: Gap = 2 REsGap between resources is applied CSI-RS resource setting (Set-specificpart) Set index: 0 Density reduction parameter: Shift value = RE Setindex: 1 Density reduction parameter: Shift value = 2 REs

FIG. 23 is a diagram illustrating a case in which two resource sets areset in one OFDM according to an embodiment of the disclosure.

Referring to FIG. 23, according to Table 17, in which a case in whichthe gap between the resource groups is set between two sets for FDM.Here, the resource group means K resources which consists of resourceindexes 0, 1, . . . , K−1 and is consecutive on the frequency axis. Forexample, the RE mapping is performed between the resource groupsbelonging to the same set while being spaced by gap=8 REs. In addition,in order to avoid the RE mapping overlapping between different sets,they have different RE mapping start indexes (=Shift values) for eachset, and these values are set differently for each set. In general, whenthe S_(FDM) resource sets are set in one OFDM symbol,gap=P×K×(S_(FDM)−1) REs may be commonly set for all sets, and the shiftvalue may be set for each set as 0 RE, P ? K REs, . . . ,P×K×(S_(FDM)−1) REs.

TABLE 17 CSI-RS resource setting Type: Beam management QCL info: SSblock index 0 Resource allocation: ( )-th Slot, ( )-th Symbol, N = 1Time-domain repetition indicator : 0 Number of resources per symbol (K):4 CDM between K resources is not applied Number of antenna ports perresource (P): 2 Sub-carrier spacing (f_s): 240 KHz Sub-time unit order(L): 1 Tx period: 10 ms periodic Density reduction method: Gap = 8 REsGap between resource groups is applied CSI-RS resource setting(Set-specific part) Set index: 0 Density reduction parameter: Shiftvalue = 0 RE Set index: 1 Density reduction parameter: Shift value = 8REs

Meanwhile, the CSI-RS resource setting proposed in the disclosure mayconsist of parameters as shown in the following Table 18. The parametersindicated by (1) in the following Table 18 may be implicitly determinedin a specific type of configuration method (e.g., cell-specificallyconfigured). Meanwhile, the parameters indicated by the above (1) may beexplicitly indicated by the base station in another type ofconfiguration method (e.g., UE-specifically configured). The gap and theshift value may be automatically determined depending on the value ofthe parameter S_(FDM) indicated by the above (2).

Gap=“P×(S_(FDM)−1)” REs

Shift=“P×(j−1)” REs for the j-th FDMed set

In this case, the gap is regarded as a parameter indicating theseparation between the resources belonging to the same set, and theshift value is regarded as an index which starts RE mapping and has thesame values as j=1, 2, . . . , S_(FDM). According to another embodimentof the disclosure, the gap and the shift value may be automaticallydetermined as follows depending on the value of the parameter S_(FDM)indicated by the above (2). At this time, the gap is regarded as theparameter indicating how frequently the resource group is repeatedlymapped, having how far the resource group is spaced apart from thefrequency base.

Gap=“P×(S_(FDM)−1)” REs

Shift=“P×(j−1)” REs for the j-th FDMed set

The symbol index indicated in the resource allocation shown in thefollowing Table 18 indicates a symbol index at which the RE mapping forS sets starts.

The CSI-RS set based on the parameters shown in the following Table 18has the following characteristics.

-   -   RE mapping pattern may be defined within a configured CSI-RS BW        regardless of RB grid.    -   For some use cases (e.g., P1 BM), OFDM symbol is configured with        CSI-RS only within a configured CSI-RS BW.    -   A resource set can be defined within N OFDM symbols which        comprise NK resources.

(FFS N>1 is needed in NR spec. If it is needed, N maybe configurableparameter)

-   -   Each resource can represent a beam identity of a specific TRP.    -   Multiple resource sets may be configured in a single resource        setting, and they can share the same RE mapping pattern.    -   Multiple resource sets may be configured in N OFDM symbol with        FDM manner.    -   Sub-time unit details

Time-unit is determined by indicated SCS, and tx beams may be changedbetween time-units

(i.e., within a time-unit, tx beams are not changed)

Number of sub-time units in a time-unit is defined by indicatedrepetition factor

(e.g., 1, 2, 4), and Rx beams may be changed across sub-time units

IFDM is used for partitioning method of sub-time units

TABLE 18 Total number of configured resource sets⁽¹⁾: S Resourceallocation⁽¹⁾: Slot index & Symbol index Number of symbols per resourceset⁽¹⁾: N Number of antenna ports per resource (P) and number ofresources per symbol (K): Option 1 (resource based beam identity): P ={1, 2} and K = {2, 4, 8} Option 2 (port & resource based beam identity);P = {2, 4, 8, 16} Time-domain repetition indicator for N symbols Ifrepetition is activated, a resource set in one OFDM symbol is repeatedin N symbols If repetition is not activated, N × K resources are definedin a resource set within N symbols Sub-carrier spacing (f_s⁽¹⁾) for atime-unit & Number of sub-time unit per time-unit (L⁽¹⁾) Index 0 1 2 3 45 f_s [KHz] 60 60 60 120 120 240 L  1  2  4  1  2  1 Tx period: {5, 10,20 ms} periodic Number of FDMed resource sets in a OFDM symbol⁽²⁾:S_(FDM)

Meanwhile, unlike the method shown in the Table 18, the following Table19 may be used as a method of configuring f_s value and L values. Here,J fSS-block means sub-carrier spacing used for the SS-blocktransmission.

FIGS. 24, 25, 26, 27, 28, and 29 are diagrams illustrating a resourceindex and a resource set index of the CSI-RS transmitted in one slotaccording to various embodiments of the disclosure.

TABLE 19 Configuration index 0 1 2 3 4 5 f_(s) 1/4 × f_(SS-block) 1/4 ×f_(SS-block) 1/4 × f_(SS-block) 1/2 × f_(SS-block) 1/2 × f_(SS-block)f_(SS-block) L 1 2 4 1 2 1

Referring to FIG. 24, in the case of N=1, K=4, P=2, L=1, f_s=datachannel SCS, SFDM=1, and S=14, the resource index and the resource setindex of the CSI-RS transmitted in one slot are indicated.

Referring to FIG. 25, in the case of N=1, K=8, P=2, L=1, f_s=datachannel SCS, SFDM=1, and S=14, the resource index and the resource setindex of the CSI-RS transmitted in one slot are indicated.

Referring to FIG. 26, in the case of N=1, K=4, P=2, L=2, f_s=datachannel SCS, SFDM=1, and S=14, the resource index and the resource setindex of the CSI-RS transmitted in one slot are indicated.

Referring to FIG. 28, in the case of N=2, K=4, P=2, L=1, f_s=datachannel SCS, SFDM=1, and S=7, the resource index and the resource setindex of the CSI-RS transmitted in one slot are indicated. In this case,“Time-domain repetition indicator for N symbols” may be set to be OFF.

Referring to FIG. 29, in the case of N=2, K=4, P=2, L=1, f_s=datachannel SCS, SFDM=1, and S=7, the resource index and the resource setindex of the CSI-RS transmitted in one slot are indicated. In this case,“Time-domain repetition indicator for N symbols” may be set to be ON.

Fourth Embodiment: Activation Request of SP-CSI-RS Resource

Based on the resource setting method described above, the base stationcan operate the CSI-RS configured by two different schemes asillustrated in the following Table 20. In this case, the CSI-RScell-specifically configured may be used in the MIB or SIB for the P1BM, and the CSI-RS UE-specifically configured may be used in the RRC forthe P2 BM. The CSI-RS for the P1 BM may be UE-specifically configuredusing the RRC. The CSI-RS for the P1 BM may include resource sets asmany as the SS-blocks transmitted by the base station. For example, ifthe base station periodically transmits a total of T SS-blockscorresponding to index 0, 1, . . . , T−1, the base station mayperiodically transmit the CSI-RS resource sets corresponding to theresource set indexes 0, 1, . . . , T−1 for the P1 BM.

A semi-persistent transmission scheme is established in the base stationfor the cell-specifically configured CSI-RS resource sets, and theinformation on whether each resource set is activated may be broadcastto the terminals in the SIB. The information on whether each resourceset is activated may use a bitmap having a size corresponding to thenumber of resource sets configured in the corresponding cell. Forexample, when a total of 64 resource sets are configured, the basestation may use a bitmap having 64 bits to indicate an indexcorresponding to an activated resource set by 1, and an indexcorresponding to a deactivated resource set by 0 The terminals mayperform measurement and reporting on the activated resource set. Inaddition, the terminal may measure the received signal strength of theSS block and determine the best SS block index based on the receivedsignal strength. When the CSI-RS resource set having the QCLrelationship with the best SS block index is in the deactivation state,the terminal may transmit information requesting the activation of thecorresponding CSI-RS resource set to the base station. The CSI-RS may beUE-specifically configured using the RRC. It may be UE-specificallytransmitted whether each CSI-RS resource set is activated through theRRC signaling or the MAC CE. The base station may use a bitmap having alength T to transmit the information on whether the CSI-RS resource setscorresponding to the CSI-RS resource set indexes 0, 1, . . . , T−1 forthe P1 BM is activated to the terminal as shown in the following Table22. For example, when the CSI-RS resource set corresponding to an indext is activated, a t-th bit value of the bitmap having the length T has“1”, and when a CSI-RS resource set corresponding to the index t isdeactivated, the t-th bit value of the bitmap having the length T has“0”.

TABLE 22 CSI-RS_active= {00111010....... 0}

Meanwhile, the UE-specifically configured CSI-RS may be used for the P2BM. If the CSI-RS for the P1 BM is cell-specifically configured, the QCLinformation with the cell-specifically configured CSI-RS resource set asdescribed in option 2 of the following Table 20 in the resource settingof the CSI-RS for the P2 BM may be included. Meanwhile, the base stationmay include the QCL information with the SS-block as described in option1 of the following Table 20 in the resource setting of the CSI-RS forthe P2 BM.

According to another embodiment of the disclosure, the CSI-RS for the P1BM as shown in the following Table 21 may be UE-specifically configuredusing dedicated RRC signaling.

FIG. 31 is a diagram illustrating QCL information between K1 CSI-RSresources for P1 BM and K2 resources for P2 BM according to anembodiment of the disclosure.

Referring to FIG. 31, some of the P2 BM resources can be set to be inthe deactivated state. The terminal may select the best CSI-RS resourceindex by performing the beam search on the K1 CSI-RS resources for theP1 BM. In addition, the information on whether the corresponding CSI-RSresource having a P2 level is set to be in the activation state may beidentified by the QCL relationship with the selected CSI-RS resourceindex having a P1 level. If the CSI-RS resource having the P2 level isset to be in the deactivation state, the terminal may request theactivation of the corresponding resource to the base station. Theoperation of the base station and the terminal associated therewith isshown in FIGS. 3A and 3B. The base station sets the CSI-RS resource (orresource set) for the P1 BM and the CSI-RS resource (or resource set)for the P2 BM in the terminal and indicates whether each resource (orresource set) is activated to the terminal. The terminal performs thebeam search on the resource (or resource set) having the P1 level whichis set to be in the activation state to select the resource (or resourceset) corresponding to the best beam. It is identified whether thecorresponding resource (or resource set) having the P2 level is set tobe in the activation state by the QCL relationship with the selectedresource (or resource set) having the P1 level. If the resource (orresource set) having the P2 level is set to be in the deactivationstate, the terminal may transmit to the base station the signalingrequesting the switching to the activation state for the resource (orresource set) having the P2 level. In this embodiment of the disclosure,the beam search and the best index selection for the CSI-RS for the P1BM may be replaced with the beam search and the best index selection forthe SS-block for the P1 BM. At this time, the base station may notifythe terminal of the QCL information between the SS-block index of the P1BM and the resource (or resource set) for the P2 BM, and the terminalmay use the QCL information to transmit to the base station thesignaling requesting the switching to the activation state for theresource (or resource set) having the P2 level by the same method.

When the QCL relationship between the SS block and the SP-CSI-RS isdefined, the terminal may perform the activation request or thedeactivation request for the SP-CSI-RS resource set based on themeasurement information on the SS block. The request may be transmittedin the form of the MAC CE. If the base station periodically transmitsthe SS-blocks corresponding to the SS-block indexes 0, 1, . . . , T, thebase station may transmit to the terminal the information on whether theCSI-RS resource sets corresponding to the CSI-RS resource set indexes 0,1, . . . , T for the P1 BM is activated using the bit map having thelength T. For example, if the t-th CSI-RS resource set is activated, thet-th bit value of the bitmap having the length T has “1”, and if thet-th CSI-RS resource set is deactivated, the t-th bit value of thebitmap having the length T has “0”.

The number of CSI-RS resource sets in the activation state set in oneterminal may be set to be K by the base station, where K<=T. The indexset of the SS blocks corresponding to the currently set K active CSI-RSresource sets is defined as follows.

SS_active={i1, i2, . . . , iK}

The base station may explicitly transmit the information on theSS_active set to the terminal. Alternatively, the terminal mayimplicitly identify the information on the SS_active set based on theindex information of the SS block corresponding to the activatedSP-CSI-RS resource set by the QCL relationship. The set of the indexesthat are not included in the SS_active among all the T SS block indexesis named the SS_deactive in the following description.

In the following description, RSRP_i refers to the RSRP value measuredby the terminal for the SS block corresponding to an SS block index i.

[Method 1a]

-   -   The terminal selects N SS blocks corresponding to the upper N        RSRP values based on the measured RSRP values of all SS blocks.        At this time, the base station may set a value corresponding        to N. (e.g., N=1).    -   The terminal configures as a Request_SS_active set the indexes        that are not included in the SS_active set among the selected        upper N SS block indexes.    -   Reporting method of Request_SS_active set        -   Method 1) When the base station requests reporting, the            terminal transmits the reporting. The transmission for the            reporting may be performed periodically or may be            transmitted aperiodically only when the base station            requests the reporting.        -   Method 2) When the number of indexes included in the            Request_SS_active set configured by the terminal is equal to            or greater than the N_reporting number, the terminal            transmits the Request_SS_active set to the base station            through the MAC CE.        -   The N_reporting value may be preset by the base station            through the RRC or the MAC CE.    -   When the information on the Request_SS_active set is reported,        all or some of the following information included in the        following Table 23 may be transmitted to the base station.

TABLE 23 Request_SS_active set RSRP values measured for the SS blockscorresponding to the index included in the SS_active RSRP valuesmeasured for the SS blocks corresponding to the index included in theRequest_SS_active set

[Method 1b]

-   -   The highest value among the RSRP values measured by the terminal        for the SS blocks corresponding to the indexes included in the        SS_active set is defined as reference RSRP as shown the        following Equation (1).

RSRP_ref=max(RSRP_i) for all i∈SS_active  Equation 1

Among the RSRP measurement values for the SS blocks corresponding to theindex included in the SS_deactive set, the indexes of the SS blockscorresponding to the RSRP values higher above the threshold set by thebase station than the reference RSRP value is configured as theRequest_SS_active set (see Table 24).

TABLE 24 Request_SS_active= {j | RSRP_j > RSRP_ref+ Threshold} for all jϵ SS_deactive

-   -   If the SS_block_index equal to or greater than the N_reporting        number is included in the Request_SS_active set, the terminal        transmits the Request_SS_active set to the base station using        the MAC CE.        -   The N_reporting value may be preset by the base station            through the RRC or the MAC CE.

In the above embodiment of the disclosure, the value for the “RSRP_ref”may be set to be a specific value in advance by the base station.

In the above embodiment of the disclosure, the base station may changethe SP-CSI-RS currently set in the deactivation state to the activationstate based on the Request_SS_active reporting and set it. The change ofthe activation setting may be performed by the MAC-CE, and the terminalcan update the SS_active set and the Request_SS_active set based on thechanged setting.

According to another embodiment of the disclosure, one SS block indexmay have the QCL relationship with one or more SP-CSI-RS resources. TheQCL relationship may be transmitted to the terminal in advance throughthe RRC or MAC CE. The total number of SS blocks transmittedperiodically by the base station may be smaller than the T2 valuedescribed below.

The base station may use the bitmap message having the length T2 asshown in the following Table 22 to transmit whether the CSI-RS isactivated to the terminal. At this time, when the t-th CSI-RS resourceis activated, the t-th bit value of the bitmap having the length T2 has“1”, and when the t-th CSI-RS resource is deactivated, the t-th bitvalue of the bitmap having the length T2 has “0”.

[Method 2a]

-   -   The terminal selects N SS blocks corresponding to the upper N        RSRP values based on the measured RSRP values of all SS blocks.        At this time, the base station may set a value corresponding        to N. (e.g., N=1).

The terminal selects the CSI-RS resource indexes having the QCLrelationship with the upper N SS block indexes.

-   -   The indexes of the CSI-RS resource sets in the deactivation        state among the selected CSI-RS resource indexes are collected        and configured as the Request_CSI-RS_active set as shown the        following Table 25.    -   When the number of indexes included in the Request_SS_active set        configured by the terminal is equal to or greater than the        N_reporting number, the terminal transmits the Request_SS_active        set to the base station through the MAC CE.        -   The N_reporting value may be preset by the base station            through the RRC or the MAC CE.

TABLE 25 Request_CSI-RS_active= {CRI_j1, CRI_j2..., }

In the following description, the CSI-RS_RSRP_i refers to the RSRP valueobtained by averaging the RSRP values measured by the terminal in allantenna ports included in the CSI-RS resource corresponding to theCSI-RS resource index i. In the following description, it is assumedthat the terminal may measure the RSRP value for the deactivated CSI-RS.In order to measure the RSRP value of the terminal, the base station maytransmit to the terminal the information on whether the RSRP value canbe measured in the deactivated CSI-RS to the MS.

[Method 2c]

The terminal defines the highest value among the RSRP measurement valuesfor the activated CSI-RS resources as the reference RSRP.

RSRP_ref=max(CSI-RS_RSRP_i) for all CRI i's corresponding to theactivated CSI-RS resources  Equation 2

-   -   The RSRP measurement is performed on the deactivated CSI-RS        resources, and the index of the CSI-RS resource corresponding to        the RSRP values higher than the reference RSRP value of the        above Equation 2 above the threshold set by the base station is        configured as the Request_CSI-RS_active set as shown in the        following Table 26.    -   When the number of indexes included in the Request_SS_active set        configured by the terminal is equal to or greater than the        N_reporting number, the terminal transmits the Request_SS_active        set to the base station through the MAC CE.

TABLE 26 The N_reporting value may be preset by the base station throughthe RRC or the MAC CE.

In the above embodiment of the disclosure, the value for the “RSRP_ref”may be set to be a specific value in advance by the base station.

Fifth Embodiment: OFDM Symbol Used for Dedicated CSI-RS Transmission

The terminal may assume that the signal/channel other than the CSI-RS isnot FDMed in the OFDM symbol in which the CSI-RS resource for the P1 orP2 BM is configured. For example, the terminal receiving the PDSCHscheduling for the slot including the OFDM symbol in which the CSI-RS isconfigured may perform decoding on the assumption that the PDSCH signalis transmitted only to the remaining symbols other than thecorresponding OFDM symbol in a slot. Meanwhile, if the transmission forthe CSI-RS resource set is deactivated, the terminal may assume thatanother signal/channel other than the CSI-RS is transmitted to the OFDMsymbol in which the corresponding CSI-RS is configured. For example, theterminal receiving the PDSCH scheduling for the slot including the OFDMsymbol in which the deactivated CSI-RS resource set is configured mayperform decoding on the assumption that the PDSCH signal is transmittedeven to the corresponding OFDM symbol in a slot.

FIG. 30 is a diagram illustrating a process of performing resourcesetting having an index of S1, S2, . . . , SN according to an embodimentof the disclosure.

Referring to FIG. 30, a base station 3000 may perform resource settinghaving indexes of S1, S2, . . . , SN. The information on the resourceset index set in the activation state in which a double transmission isactually performed may be transmitted to the terminal 3010 as {Sactive}.When the terminal 3010 receives scheduling from the base station 3000 ina slot in which the resource set belonging to the received {Sactive}index set is set, the terminal 3010 may perform decoding on theassumption that the PDSCH signal is transmitted only to the remainingsymbols other than the OFDM symbol in the slot. The base station 3000may dynamically indicate the {Sactive} information to the terminal 3010whenever the {Sactive} information is updated. The base station 3000 mayset the CSI-RS BW to which the CSI-RS is transmitted for each resourceset when performing the resource setting. The CSI-RS BW may be differentfor each resource set, or the same CSI-RS BW may be set for eachresource set. When the terminal 3010 is in the active state for theresource set in which the CSI-RS BW is set, the terminal 3010 mayperform decoding on the assumption that the PDSCH is transmitted to theOFDM symbol in which the resource set is configured in the remainingfrequency period other than the CSI-RS BW. Meanwhile, the base station3000 may set whether the FDM transmission of the CSI-RS and the PDSCH ispossible for each resource set when performing the resource setting. Forexample, for the resource set which is set to disable the FDMtransmission of the CSI-RS and the PDSCH, the decoding may be performedon the assumption that the PDSCH is not transmitted to the entire systemBW or the configured CSI-RS BW in the OFDM symbol in which thecorresponding resource set is configured as described above. Meanwhile,for the resource set which is set to enable the FDM transmission of thePDSCH, the decoding may be performed on the assumption that the PDSCHtransmission is performed on the remaining REs other than the RE inwhich Non-zero power CSI-RS or Zero power CSI-RS transmission isperformed.

TABLE 20 Cell-specifically configured US-specifically configured CSI-RSor PI BM CSI RS for P2 BM Configuration MIB or SIB RRC methodTransmission Periodic, Semi-persistent Periodic, Semi-persistent, periodAperiodic Upon Broadcasting whether each Transmitting whether eachSemi-persistent resource set is activated in resource is activated inRRC transmission, SIB using bitmap as many or MAC CE using bitmap asActivation/ ast he number resource many as the number of Deactivationsets configured in cell resource sets configured in method terminalSub-time Disable In case of Periodic or semi unit order persistenttransmission, RRC setting method or MAC CE can be used In case ofAperiodic transmission, RRC, MAC CE, or DCI can be used QCL IndicationQCL information with Option 1, QCL information SS-bock with SS-blockOption 2, QCL information with Cell-specifically configured CSI-RSresource set

TABLE 21 Cell-specifically configured US-specifically configured CSI-RSor PI BM CSI RS for P2 BM Configuration RRC method TransmissionPeriodic, Semi-persistent Periodic, Semi-persistent, period AperiodicUpon Transmitting whether each resource is activated in Semi-persistentRRC or MAC CE using bitmap as many as the transmission, number ofresource sets configured in terminal Activation/ Deactivation methodSub-time Disable In case of Periodic or semi- unit order persistenttransmission. RRC setting method or MAC CE can be used In case ofAperiodic transmission, RRC, MAC CE, or DCI can be used QCL IndicationQCL information with SS- Option 1, QCL information bock with SS-blockOption 2, QCL information with resource set for “UE- specificallyconfigured CSI- RS for P1 BM” resource set

Sixth Embodiment: RE Mapping Method of CSI-RS for Beam Management

According to the CSI-RS setting method proposed in the disclosure, oneCSI-RS resource (or port group) may be allocated to one OFDM symbol.

FIG. 32 is a diagram illustrating a CSI-RS resource setting between abase station and a terminal according to an embodiment of thedisclosure.

FIG. 33 is a diagram illustrating a case in which K CSI-RS resources (orport groups) are allocated to one OFDM symbol according to an embodimentof the disclosure.

Referring to FIGS. 32 and 33, an embodiment for a case in which K=1, 2,4, and 8. K resources (or port groups) are sequentially and repeatedlymapped to one OFDM symbol on frequency is illustrated. The OFDM symbollength in which one CSI-RS is transmitted is referred to as a time unit,and the length of the time unit is determined by a fs value set by thebase station as described above.

FIG. 34 is a diagram illustrating a case in which one resource or a portgroup is mapped to NP×L REs according to an embodiment of thedisclosure.

Referring to FIG. 34, one resource or port group is mapped to N_(P)×LREs, which is illustrated in FIG. 34. Here, a value indicated byf_(CSI-RS, BM) has the same meaning as f_(s) described above, but onlynotation is represented differently. N_(P) means the number of antennaports that may be included in one resource (or port group), and L meansthe number of sub-time units that may be set in one time unit. Asdescribed above, the terminal may perform the Rx beam sweeping up to Ltimes within one time unit.

For the RE mapping of the CSI-RS for the beam management, the samemethod as the following Table 27 may be used. This corresponds to thecase in which K=1 in the above embodiment.

TABLE 27 CSI-RS resource with 1-port and 2-port for one OFDM symbol maybe used for beam management  For the case of 1-port No CDM Subcarrierspacing within a PRB for D>1  Even spacing L Constant subcarrier spacingacross PRB(s)  Constant subcarrier spacing within a BWP FFS the valuesof D For the case of 2-port: No CDM Subcarrier spacing within a PRB forD>1 Even spacing 2L between the same port Even spacing L betweendifferent ports Constant subcarrier spacing across PRB(s) Constantsubcarrier spacing within a BWP FFS the values of D

The RE mapping for the non-zero power CSI-RS (NZP CSI-RS) for thespecific OFDM symbol may be set as shown in the following Table 27. Theabove setting may be performed as shown in the following Table 28. Thesetting may include time base information “Symbol_location_info” and“Slot_location_info” on a symbol and a slot to which K resources aretransmitted. If the K resources are periodic or semi-persistent CSI-RS,the setting may include a parameter “Periodicity” associated with thetransmission period. If the K resources are periodic or aperiodicCSI-RS, the setting may not include the value for the parameter“Periodicity”. For the setting of the RE mapping method for the Kresources, the setting may include a field “nzp_resourceConfig”. Thefield may include a parameter K [resources] for indicating how manyresources are transmitted at the set symbol location. The field mayinclude a value for a parameter X [ports] indicating how many antennaports the resources are configured. At this time, each of the Kresources may consist of resources having X [ports]. The field mayinclude a value for D [REs/RB/port] to set a density for one antennaport. For example, each of the antenna ports included in the K resourcesare transmitted at a symbol location set at a density of D. In the caseof X=1 [port], the value D may be represented by D=12/(LK) [RE/RB/port]based on parameters illustrated in FIGS. 33 and 34. For any X=[port]value, the value D may be represented by D=12/(LXK) [RE/RB/port] basedon the parameters illustrated in FIGS. 33 and 34. The field may includean RE_mapping_offset [REs] parameter, which includes the information onthe RE position at which the RE mapping for the K resources starts. Forexample, for a total of M PRBs corresponding to PRB index “I” to PRBindex “I+M ? 1”, if the K resources are transmitted while being REmapped as shown in FIGS. 33 and 34, the location at which the RE mappingstarts is RE_mapping_offset [REs]-th RE in the PRB corresponding to thePRB index I. For example, when the RE_mapping_offset values are setdifferently in different CSI-RS settings and all the remainingparameters are equally set, locations at which the CSI-RSs transmittedat each setting are RE mapped may be made not to overlap with eachother. In this case, the RE_mapping_off value is 0, 1, . . . , L−1 basedon the parameter L value of FIG. 34.

TABLE 28 CSI-RS-ConfigNZP-BM = {  Symbol_location_info= { } Slot_location_info = { }  Periodicity = { }  nzp-resourceConfig = { D ={ }, K = { }, X = { }, RE_mapping_offset = { } } }

The base station may allocate zero power CSI-RS (ZP CSI-RS) resources tothe remaining REs other than the REs corresponding to the RE mapping ofthe NZP CSI-RS resource. The base station may notify the terminalwhether the ZP CSI-RS resource is set in the remaining RE when settingthe NZP CSI-RS resource. The setting of the resource may be performed asshown in Table 29. The “nzp-resourceConfig” field sets the RE positioncorresponding to one or more NZP CSI-RS resource (s). The“zp-resourceConfig” field is a field for setting whether the ZP CSI-RSresource corresponds to the RE positions other than the RE positionscorresponding to the NZP CSI-RS resource (s). For example, when“zp-resourceConfig={On}”, the one ZP CSI-RS resource is set tocorrespond to the remaining RE positions.

TABLE 29 CSI-RS-Config-BM = { Symbol_location_info = { } Slot_location_info = { }  Periodicity = { }  nzp-resourceConfig= { D ={ }, K = { }, X = { }, RE_mapping_offset = { } }  zp-resourceConfig={On, Off} }

If the base station simultaneously sets the ZP CSI-RS and the NZP CSI-RSin the terminal using the following Table 29, the terminal may beassumed that a time domain repeating pattern appears L times in the OFDMsymbol interval.

FIG. 36 is a diagram illustrating a case in which L=4 sub-time unit OFDMsymbols are generated within one OFDM symbol interval according to anembodiment of the disclosure.

Referring to FIG. 36, when the related parameter is set to be L=4 in thefollowing Table 27, if the CSI-RS is set in the terminal using themethod 2, the terminal sets a sub-time unit OFDM symbol having L=4 inone OFDM symbol interval. The terminal may apply different terminalreception beams for each sub-time unit and may search for an optimalterminal reception beam by comparing the received strength for each subtime unit.

According to the CSI-RS setting method proposed in the disclosure, aplurality of resource sets may be set in one OFDM symbol as describedabove. In the disclosure, the term resource group may be replaced byanother expression having the same meaning as the resource set describedabove.

FIG. 35 is a diagram illustrating an embodiment of a case in which tworesource groups are set in one OFDM symbol according to an embodiment ofthe disclosure. Each resource group may be transmitted from a differentbase station antenna panel or TRP.

Referring to FIG. 35, according to another embodiment of the disclosure,the resource setting of the CSI-RS having K resources in one OFDM symbolmay be set as follows. The following setting may be equally applied toseveral OFDM symbols. At this time, the setting described below as shownin the following Table 31 may further include the information on theOFDM symbol location and the slot location.

The following Table 30 shows the methods for setting the K CSI-RSresources in one OFDM symbol based on the RE mapping method for thesingle antenna port described in the following Table 27. The value of D[REs/RB/port] indicating the density at which one antenna port is REmapped on the frequency base is determined according to theconfiguration index value, and the K value as the number of resources tobe set in one OFDM symbol is determined. In order to prevent thecollision of the RE-mapped locations on the frequency base between the Kresources, different RE mapping offset (δ_(k)) for each resource aredetermined based on values in the following Table 30. For example,according to Configuration index No. 0, K=2 resources are set in oneOFDM symbol. In the bandwidth in which the CSI-RS is set, a firstresource means that the RE mapping starts from RE No. 0, and a secondresource means that the RE mapping starts from RE No. 1. Since the aboveparameters are automatically determined when only the Configurationindex value is given, it is sufficient to include only the Configurationindex value in the CSI-RS resource setting.

Meanwhile, all of the K resources may be set as the non-zero power (NZP)CSI-RS, and some thereof may be set as zero power (ZP) CSI-RS. In orderto increase the accuracy of L1-RSRP measurement in a serving cell andfacilitate measurement for the interference of neighboring cells, theallocation pattern of the NZP CSI-RS and ZP CSI-RS between cells may notoverlap each other. As the method, a bitmap “b₀b₁ . . . b_(K-1)” havinga length K may be included in the CSI-RS resource setting. If bk is setto be “1” in the bitmap, the (k+1)-th resource set in the CSI-RSresource setting is set to be the NZP CSI-RS. If bk is set to be “0” inthe bitmap, the (k+1)-th resource set in the CSI-RS resource setting isset to be the ZP CSI-RS.

The CSI-RS resource setting may be equally set in different terminals.The CSI-RS may be set as the SP CSI-RS, and only some resources thereofmay be UE-specifically activated.

Table 30: Configuration for K SP CSI-RS resources with single antennaport (Type-1)

TABLE 30 Number of configured RE Number of resources mapping antenna onone offset D ports per OFDM for Configuration [REs/RB/ resource symboleach index⁽¹⁾ port] (X) (K) resource 0 6 1 2 0, 1 1 3 1 4 0, 1, 2, 3 21.5 1 8 0, 1, 2, 3, 4, 5, 6, 7 3-7 Reserved Reserved Reserved Reserved

(1) Need to be Included in the CSI-RS Resource Setting

The above embodiment may be used as the setting method for P CSI-RS orAP CSI-RS in which the periodic transmission is performed. For example,the resource setting of the CSI-RS may be performed as shown in thefollowing Table 31.

TABLE 31 CSI-RS-Config-BM = {  Symbol_location_info = { } Slot_location_info = { }  Periodicity = { }  nzp-resourceConfig = {  Configuration index = { },  }  zp-resourceConfig = b₀b₁...b_(K−1) }

According to another embodiment of the disclosure, in the resourcesetting of the CSI-RS having K resources in one OFDM symbol, values ofeach D, K, and δ_(k) may be set as shown in the following Table 32.Unlike the above Table 30, in the setting related to the following Table32, values for Configuration index (or D), K, X, and δ_(k) should bespecifically included at the time of the resource setting of CSI-RS. Atthis time, the REs that are not used for the RE mapping for the Kresources may be generated in the OFDM symbol in which the CSI-RS is setaccording to which value K is set to be. The resource setting of theCSI-RS may include a “zp-resourceConfig” field that may be representedby 1 bit. If the value of this field is set to be “On”, the terminal mayassume that the ZP CSI-RS is set for the REs not used for the RE mappingof the K resources. On the other hand, if the value of this field is setto be “OFF”, it means that the terminal should not make any assumptionabout the REs not used in the RE mapping of the K resources.

TABLE 32 Configuration for K P/AP CSI-RS resources with single antennaport (Type-2) Number of Number of RE mapping antenna configured offsetfor ports per resources on each Configuration D resource one OFDMresource⁽¹⁾ index⁽¹⁾ [REs/RB/port] (X) symbol⁽¹⁾ (K) (δ_(k)) 0 6 1 K ={1, 2} δ_(k) = {0, 1} 1 3 1 K = {1, 2, 4} δ_(k) = {0, 1, 2, 3} 2 1.5 1 K= {1, 2, 4, δ_(k) = {0, 1, 2, 8} 3, 4, 5, 6, 7} 3-7 Reserved ReservedReserved Reserved

(1) Need to be Included in the CSI-RS Resource Setting

The above embodiment may be used as the setting method of the AP CSI-RSin which the periodic transmission is performed. For example, theresource setting of the CSI-RS may be performed as shown in thefollowing Table 33. The following setting may be equally applied toseveral OFDM symbols. At this time, the setting described below as shownin the following Table 33 may further include the information on theOFDM symbol location.

TABLE 33 CSI-RS-Config-BM = {  Symbol_location_info = { } nzp-resourceConfig = {   Configuration index⁽¹⁾ = { }  Number_Antenna_Ports (X) = { }   Number of resources on one OFDMsymbol (K) = { }   RE_mapping_offset = { δ₀, δ₁, ..., δ_(K−1) }  } zp-resourceConfig = {On, Off} }

(1) Replaced by D [REs/RB/Port] Parameter

According to another embodiment of the disclosure, in the resourcesetting of the CSI-RS having K resources in one OFDM symbol, theparameters shown in the following 34 may be used. The resource settingof the CSI-RS may be performed as shown in the following Table 35. Forexample, if only the value for the “Configuration index” is instructedto the terminal, the terminal may find the values for the remainingparameters D, X, K, and δk based on the following Table 34.

TABLE 34 Number of Number configured RE of resources mapping antenna onone offset D ports per OFDM for each Configuration [REs/RB/ resourcesymbol resource index⁽¹⁾ port] (X) (K) (δ_(k)) 0 6 1 K = 1 δ₀ = 0 1 δ₀ =1 2 K = 2 δ₀ = k 3 3 for k = 0, 1 4 K = 1 δ₀ = 0 5 δ₀ = 1 6 δ₀ = 2 δ₀ =3 7 K = 2 δ₀ = 0, δ₁ = 2 8 δ₀ = 1, δ₁ = 3 9 K = 4 δ_(k) = k for k = 0,1, 2, 3 10 1.5 K = 1 δ₀ = 0 11 δ₀ = 1 12 δ₀ = 2 13 δ₀ = 3 14 δ₀ = 4 15δ₀ = 5 16 δ₀ = 6 17 δ₀ = 7 18 K = 2 δ₀ = 0, δ₁ = 4 19 δ₀ = 1, δ₁ = 5 20δ₀ = 2, δ₁ = 6 21 δ₀ = 3, δ₁ = 7 22 K = 4 δ₀ = 0, δ₁ = 2, δ₂ = 4, δ₃ = 623 δ₀ = 1, δ₁ = 3, δ₂ = 5, δ₃ = 7 24 K = 8 δ_(k) = k for k = 0, 1, . . ., 7

TABLE 35 CSI-RS-Config-BM = {  Symbol_location_info, Slot_location_info,  Periodicity,  nzp-resourceConfig = {  Configuration index  }  zp-resourceConfig = {On, Off} }

Meanwhile, in the above embodiments of the disclosure, the“Slot_location_info” field included in the resource settings related tothe P/SP CSI-RS in which the periodic transmission is performedtransmits to the terminal the location information of the slots throughwhich the CSI-RS set in the resource setting. The “Slot_location_info”field may be configured as shown in the following Table 36. For example,the start location at which the slots are allocated is indicated as“Starting_slot_index”, and the number of slots continuously allocatedfrom the start location may be indicated as“Number_of_consecutive_Slots”. For example, in the case of the followingTable 36, the CSI-RSs set in the resource setting are transmitted in Yconsecutive slots starting from a X-th slot location.

TABLE 36 Slot_location_info = { Starting_slot_index = XNumber_of_consecutive_Slots = Y }

Meanwhile, the setting of the slot location may be performed as shown inthe following Table 37. For example, for the Y consecutive slots fromthe X-th slot location, the “Configured_Slots” field may specificallyindicate the slot location at which the CSI-RS is to be transmittedthrough the bit map having the Y length. For example, when bi is “1”, alocation of a “X+i”-th slot indicates the slot used for the transmissionof the CSI-RS. When bi is “0”, the location of the “X+i”-th slotindicates the terminal that the slot used for the transmission of theCSI-RS.

TABLE 37 Slot_location_info = { Starting_slot_index = X Configured_Slots= b₀b₁...b_(Y) }

In the above embodiments of the disclosure, the “Symbol_location_info”field included in the resource setting transmits to the terminal thelocation information of the OFDM symbol to which the CSI-RS istransmitted in the slots indicated by the resource setting. For example,the slots correspond to the slots indicated by, for example, the methodas shown in the above Table 36 or Table 37, and for all the slots, theCSI-RS is commonly transmitted at the OFDM symbol location indicated bythe “Symbol_location_info” field. Meanwhile, in the case of the APCSI-RS in which the aperiodic transmission is performed, the DCIindicating the transmission of the AP CSI-RS may explicitly transmit theslot location at which the AP CSI-RS is transmitted.

The information transmitted in the “Symbol_location_info” field mayconsist of bitmap b0b1 . . . b13 having a length of 14 as shown in thefollowing Table 38, for example. If the bi bit in the bitmap is set tobe “1”, it indicates to the terminal that the i-th OFDM symbol in theslots is used for the CSI-RS transmission. If the bi bit in the bitmapis set to be “0”, it indicates to the terminal that the i-th OFDM symbolin the slots is not used for the CSI-RS transmission.

TABLE 38 Symbol_location_info = {b₀b₁...b₁₃}

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a user equipment (UE) in awireless communication system, the method comprising: receiving, from abase station, channel state information reference signal (CSI-RS)resource information, the CSI-RS resource information including arepetition indicator indicating whether a repetition is on or off for aCSI-RS resource set; and measuring CSI-RSs corresponding to CSI-RSresources within the CSI-RS resource set based on the CSI-RS resourceinformation, wherein the UE assumes that the CSI-RS resources within theCSI-RS resource set are received with a same transmission beam of thebase station in case that the repetition indicator is set to on, andwherein the CSI-RS resources within the CSI-RS resource set are receivedin different OFDM symbols.
 2. The method of claim 1, wherein the CSI-RSresource information includes at least one of a synchronization sequence(SS) block index having spatially quasi-co-location (QCL) relationshipwith the CSI-RS resource set, resource allocation information for theCSI-RS resource set, and a transmission period for the CSI-RS resourceset.
 3. The method of claim 1, wherein the UE assumes that the CSI-RSresources within the CSI-RS resource set are received with differenttransmission beams of the base station in the different OFDM symbols incase that the repetition indicator is set to off.
 4. The method of claim3, further comprising: obtaining a reference signal received power(RSRP) based on a measurement of the CSI-RSs, wherein the CSI-RSresource set is configured for a beam management.
 5. The method of claim1, wherein the CSI-RS resource information is received via a radioresource control (RRC) message.
 6. A method performed by a base stationin a wireless communication system, the method comprising: transmitting,to a user equipment (UE), channel state information reference signal(CSI-RS) resource information, the CSI-RS resource information includinga repetition indicator indicating whether a repetition is on or off fora CSI-RS resource set; and transmitting, to the UE, CSI-RSscorresponding to CSI-RS resources within the CSI-RS resource set basedon the CSI-RS resource information, wherein the CSI-RS resources withinthe CSI-RS resource set are transmitted with a same transmission beam ofthe base station in case that the repetition indicator is set to on, andwherein the CSI-RS resources within the CSI-RS resource set aretransmitted in different OFDM symbols.
 7. The method of claim 6, whereinthe CSI-RS resource information includes at least one of asynchronization sequence (SS) block index having spatiallyquasi-co-location (QCL) relationship with the CSI-RS resource set,resource allocation information for the CSI-RS resource set, and atransmission period for the CSI-RS resource set.
 8. The method of claim6, wherein the CSI-RS resources within the CSI-RS resource set aretransmitted with different transmission beams of the base station in thedifferent OFDM symbols in case that the repetition indicator is set tooff.
 9. The method of claim 8, wherein a reference signal received power(RSRP) is obtained based on a measurement of the CSI-RSs, and whereinthe CSI-RS resource set is configured for a beam management.
 10. Themethod of claim 6, wherein the CSI-RS resource information istransmitted via a radio resource control (RRC) message.
 11. A userequipment (UE) in a wireless communication system, the UE comprising: atransceiver; and a controller configured to: receive, from a basestation via the transceiver, channel state information reference signal(CSI-RS) resource information, the CSI-RS resource information includinga repetition indicator indicating whether a repetition is on or off fora CSI-RS resource set, and measure CSI-RSs corresponding to CSI-RSresources within the CSI-RS resource set based on the CSI-RS resourceinformation, wherein the UE assumes that the CSI-RS resources within theCSI-RS resource set are received with a same transmission beam of thebase station in case that the repetition indicator is set to on, andwherein the CSI-RS resources within the CSI-RS resource set are receivedin different OFDM symbols.
 12. The UE of claim 11, wherein the CSI-RSresource information includes at least one of a synchronization sequence(SS) block index having spatially quasi-co-location (QCL) relationshipwith the CSI-RS resource set, resource allocation information for theCSI-RS resource set, and a transmission period for the CSI-RS resourceset.
 13. The UE of claim 11, wherein of the UE assumes that the CSI-RSresources within the CSI-RS resource set are received with differenttransmission beams of the base station in the OFDM symbols in case thatthe repetition indicator is set to off.
 14. The UE of claim 13, whereinthe controller is configured to obtain a reference signal received power(RSRP) based on a measurement of the CSI-RSs, and wherein the CSI-RSresource set is configured for a beam management.
 15. The UE of claim11, wherein the CSI-RS resource information is received via a radioresource control (RRC) message.
 16. A base station in a wirelesscommunication system, the base station comprising: a transceiver; and acontroller configured to: transmit, to a user equipment (UE) via thetransceiver, channel state information reference signal (CSI-RS)resource information, the CSI-RS resource information including arepetition indicator indicating whether a repetition is on or off for aCSI-RS resource set, and transmit, to the UE via the transceiver,CSI-RSs corresponding to CSI-RS resources within the CSI-RS resource setbased on the CSI-RS resource information, wherein the CSI-RS resourceswithin the CSI-RS resource set are transmitted with a same transmissionbeam of the base station in case that the repetition indicator is set toon, and wherein the CSI-RS resources within the CSI-RS resource set aretransmitted in different OFDM symbols.
 17. The base station of claim 16,wherein the CSI-RS resource information includes at least one of asynchronization sequence (SS) block index having spatiallyquasi-co-location (QCL) relationship with the CSI-RS resource set,resource allocation information for the CSI-RS resource set, and atransmission period for the CSI-RS resource set.
 18. The base station ofclaim 16, wherein transmission of the CSI-RS resources within the CSI-RSresource set are transmitted with different transmission beams of thebase station in the OFDM symbols in case that the repetition indicatoris set to off.
 19. The base station of claim 18, wherein a referencesignal received power (RSRP) is obtained based on a measurement of theCSI-RSs, and wherein the CSI-RS resource set is configured for a beammanagement.
 20. The base station of claim 16, wherein the CSI-RSresource information is transmitted via a radio resource control (RRC)message.